Semiconductor elements have multiple applications and utility in the electronics industry and are used in rectifiers, transistors, photodiodes, solar batteries, radiation detectors, charged particle detectors, integrated circuits and various other applications. They have been known in the industry for many years and the term semiconductor element is generally accepted throughout the industry and intended in this application to generically include semiconductor devices and parts thereof formed of host substrates comprising elements, alloys and intermetallic compounds of silicon, germanium, silicon/germanium, gallium arsenide, indium phosphide and the like. Such semiconductor elements can be of any convenient or suitable shape or form but are typically commercially used in the form of circular, rectangular or triangular wafers or disks.
In order to achieve the various electrical rectification characteristics so important to their multiple applications and utilities, semiconductor elements typically have an active impurity incorporated within the host substrate, during manufacture or later by diffusion, which impurity affects the electrical rectification characteristics of the semiconductor element. These active impurities are usually classified as donor impurities or acceptor impurities; the donor impurities including phosphorus, arsenic, antimony, silicon, tellurium, tin and the like; and, the acceptor impurities including boron, gallium, aluminum, zinc, cadmium, and the like.
The semiconductor element may have a region thereof containing an excess of donor impurities thus yielding an excess of free electrons. Such region is termed an impurity doped n-type region. Similarly, the semiconductor element may have a region thereof containing an excess of acceptor impurities, which results in a deficit of electrons, such region being termed an impurity doped p-type region. The boundary between such p-type and n-type regions is termed the n-p or p-n junction. In many applications the uniformity of the impurity distribution within the p or n type region, as well as the sharpness of the p-n or n-p junction, is critical to the efficiency of the semiconductor element.
Multiple means have been proposed for incorporating various active impurities in the semiconductor element. Typically, the active impurity may be intimately incorporated during preparation of the host substrate or may be incorporated by deposition on the host substrate during manufacture.